Schwalbe tires are excellent tires and the Marathon is a nice general purpose do all tire but I think it has too much tread for a road tire. A wide slick tire is the best tire for wet pavement.
Tire weight is not a huge issue but it does affect the speed of the tire in two ways. First the heavier tire is harder to accelerate and will slow your starts and stops. Second a heavier tire is an indication of a stiffer tire which increases the rolling resistance. It is always a balance of heavy tough tire vs low rolling resistance. I currently have 37mm Conti Sport Contacts which are a nice slick tire and in comes in several widths. However I am interested in the Marathon Supremes from Schwalbe which are very expensive but also light and claim to be very tough.
Craig